1) Field of the Invention
The present invention relates to N-substituted-3-(nitrogen-containing 5-membered ring)benzenesulfonamide derivatives, a preparation process thereof, and herbicidal compositions containing the derivatives as active ingredients.
2) Description of the Related Art
Numerous compounds have heretofore been proposed as herbicides. Regarding N-substituted benzenesulfonamide derivatives, a variety of compounds has also been reported as herbicides. N-substituted benzenesulfonamides containing a 5-membered ring bonded to the benzene ring and a pyrimidine ring or 1,3,5-triazine ring bonded to the nitrogen atom include, for example, the compounds of the following formula disclosed in GB 2 112 784 A and GB 2 112 783 A: ##STR2## wherein Q is a 5-membered ring, R.sup.3 is H, F, Cl, Br, CH.sub.3, CF.sub.3 or OCH.sub.3, R.sup.4 is H or CH.sub.3, W is O or S and A is ##STR3## in which X is CH.sub.3, OCH.sub.3 or Cl, Y is CH.sub.3, C.sub.2 H.sub.5, CH.sub.2 OCH.sub.3, OCH.sub.3, OC.sub.2 H.sub.5 or the like, and Z is CH or N.
There have conventionally been strong demands for herbicides capable of exhibiting reliable herbicidal activity even at such low application dosages as bringing about the advantage of reducing the amount present in the environment, herbicides capable of exhibiting selectivity between crops and weeds irrespective of variations in environmental conditions, herbicides free from crop injury to the second crop in double cropping, etc. The present invention has been completed with a view toward meeting such demands.
The present inventors have found that a series of compounds having a 5-membered ring on the 3-position of benzenesulfonamide as opposed to the inclusion of a 5-membered ring on the 2-position of benzenesulfonamide in the compounds disclosed in GB 2 112 784 A and GB 2 112 783 A referred to above has excellent herbicidal activity, leading to the completion of the present invention.